<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <title>引出生命周期</title>
  <script src="../js/vue.js"></script>
</head>

<body>
  <div id="root">
    <h2 :style="{opacity}">欢迎学习Vue</h2>
  </div>

  <script>
    Vue.config.productionTip = false

    new Vue({
      el: '#root',
      data: {
        opacity: 1
      },
      // Vue完成模板的解析并把真实的DOM元素放入页面后（挂载完毕）调用mounted
      mounted() {
        setInterval(() => {
          this.opacity -= 0.01
          if (this.opacity <= 0) this.opacity = 1
        }, 16)
      }
    })
  </script>
</body>

</html>